Towards stable solar water-splitting devices: elucidating the degradation kinetics in metal oxides-based photoelectrochemical devices

包括欧盟在内的发达经济体最近已经采取或将很快宣布氢（H2）战略，以实现“行业一体化”的更广泛目标。这些战略表明了全球政治向净零方法的明显转变，在这种方法中，氢气将在帮助难以电气化的部门脱碳方面发挥重要作用。然而，目前工业氢气主要是通过甲烷的蒸汽重整生产，这需要大量的碳氢化合物投入，并产生二氧化碳排放。光电化学（PEC）装置是最具挑战性但最有前途的制氢技术之一，在未来有可能实现H2能源的可持续发展。然而，到目前为止，对环境友好型PEC制氢系统的研究主要集中在提高太阳能制氢（STH）效率上，而对其稳定性，特别是降解背后的原因的研究较少。然而，作为科学家和工程师，重要的是开发考虑到整体性能的新技术，为其商业应用铺平道路。在RainDrop中，我解决了这个问题，旨在研究最先进的金属氧化物光电极及其钝化层降解的根本原因，使用一种整体的方法，预测使用基于原位和操作技术的新颖先进方法。广泛的光谱和表面探针技术将用于开发动力学和能量学之间的相互作用，特别是动力学和降解过程是如何相互影响的器件更深层次的理解。通过迭代设计，将确定降解机制的关键因素，并提出通用材料设计准则，以提高mox基PEC系统的稳定性。最终，将组装一个优化的MOx-PEC装置，以获得稳定的太阳能制氢。

Advanced economies, including European Union, have recently adopted or will soon announce hydrogen (H2) strategies targeting the broader goal of 'sector integration'. These strategies present a clear shift in global politics towards a net-zero approach in which H2 will play a major role to help decarbonize hard-to-electrify sectors. At present, however, industrial H2 is mainly produced by steam reforming of methane, which requires substantial hydrocarbon inputs and generates CO2 emissions. Photoelectrochemical (PEC) devices constitute one of the most challenging yet promising H2 production technologies, and can potentially achieve sustainable development of H2 energy in the future. However, until now, the investigation of environmentally friendly PEC systems for H2 production has been mainly focused on improving the solar-to-hydrogen (STH) efficiency while their stability and in particular the causes behind degradation, are less investigated. However, as scientists and engineers, it is important to develop new technologies in which the overall performances are taken into account, to pave the way for their commercial application. In RainDrop I tackle this issue, aiming to investigate the underlying causes of degradations of state-of-the-art metal oxides photoelectrodes and of their passivation layers, using a holistic approach that foresees the use of novel advanced methods based on in-situ and operando techniques. A wide range of spectroscopic and surface probe techniques will be used to develop a deeper understanding of the interplay between kinetics and energetics of the devices, and in particular how the dynamics and degradation processes are reciprocally influenced. Through iterative design the key factors of the degradation mechanisms will be identified and general materials design guidelines will be proposed to improve the stability of MOx-based PEC systems. Ultimately, an optimized MOx-PEC device will be assembled for obtaining a stable solar H2 generation.